Selective call receiving devices receive messages that are broadcast by a service provider. Known selective call receiving devices have at least one address that is assigned to the device so that it can determine whether a received signal includes a message that is intended for it. A base control frame and a collapse value are also assigned to the selective call receiving device wherein the base control frame determines the first frame of a received signal that the device decodes to determine whether its address is present and the base frame and collapse value determine the subsequent control frames that the device decodes. The base frame and collapse value of a device set a battery saving cycle for the device so that it is not drawing a high level of power continuously, but "wakes up" only when it needs to look for its address. It is noted that the lower the collapse value, the more frequently the device is required to wake up. In accordance with a known signaling protocol, a system collapse value is also employed wherein the system collapse value is broadcast to the device. The device uses the smaller of its own collapse value or the system collapse value with its assigned base frame to determine the subsequent control frames that determine when it is to "wake up."
In order for service providers to service existing customers as well as new customers with a limited bandwidth, channel sharing among different systems is desirable. Channel sharing among different systems refers to channel sharing among different signaling protocols and/or different subzones. Subzones are formed as subdivisions of a zone when it is desirable to increase the capacity of the service provider. Because the coverage area of a zone is most likely continuous and control information is simulcast in the subzones, problems can arise when a physical channel is shared among subzones. Those problems are similar to the problems encountered when systems having different signaling protocols share channels.
In order to mix systems so that they can share bandwidth, one could broadcast a small system collapse value such as 0 or 1. This approach would overcome batching or scheduling inefficiencies and long delays. However, small system collapse values result in reduced battery life of the device and are not always desirable.